Rotary internal combustion engine

ABSTRACT

A rotary internal combustion engine comprising a cylinder in a stator sealed between parallel end plates, a power shaft concentric with the cylinder bore and journaled in bearings in the end walls, an annular eccentric rotor fitted onto the shaft, and an annular piston concentric with and fitted over the rotor making sliding sealing engagement with both end plates. An abutment centered preferably between 10:00 and 10:30 o&#39;clock on the stator seals the space between the cylinder and piston from endplate to endplate and forms the counterclockwise end of a combustion-expansion chamber. A second abutment, centered preferably between 1:30 and 2:00 o&#39;clock, seals the space between the cylinder and piston from endplate to endplate and forms the clockwise end of the combustion-expansion chamber. The combustion chamber centered at 12:00 o&#39;clock comprises a shallow arcuate cavity adjacent the path of the piston and opening into the cylinder. Fuel injection means for the invention engine may be mounted on an endplate in advance of the first abutment or positioned on the end wall at approximately 12:00 o&#39;clock to inject forward directly into the combustion chamber. Various means for admitting compressed air into the combustion-expansion chamber and exhausting the spent gases as well as various types of abutments are also disclosed.

This patent application is a division of Ser. No. 30,993, filed Apr. 18,1979, now U.S. Pat. No. 4,286,555, which is a continuation-in-part ofSer. No. 956,206, filed Oct. 30, 1978, now abandoned.

BACKGROUND OF THE INVENTION

Rotary engines have generally suffered from inadequate sealings, shortlife seals, high friction by seals in rotor scraping the face of thecylinder and the end walls. Some engines are designed such that thecross-sectional area of the combustion expansion chamber broadens as thepower stroke advances, thereby allowing gases to expand radially intospace where they accomplish no work. Most rotary engine designs alsorequire precompressed fuel, with accompanying losses of energy,especially through loss of heat.

The rotary internal combustion engine of the present invention overcomesthe problems of previous rotary engines by providing positive sealing,durable sealing, and sealing with reduced friction. Additionally,advantages of the present invention rotary engine are design simplicity,capability of providing substantial quantities of air without theassistance of a turbocharger, and an expansion chamber that efficientlyutilizes combustion gases. Furthermore, the invention engine is suitablefor use as a diesel. Additional advantages are suitability to fuelinjection with quick acceleration, fuel economy, exceptional power percubic inch of expansion chamber, and a comparatively clean exhaust.

All of the above advantages are realized by the invention engine by thecombination of unique first and second abutments which form thecounterclockwise and clockwise ends, respectively, of theexpansion-combustion chamber in conjunction with unique exhaust means.

BRIEF DESCRIPTION OF THE PRIOR ART

Rotary engines have generally suffered from inadequate sealing, shortlife seals, high friction by seals in rotor scraping face of cylinderand scraping end walls. Some suffer from a combustion expansion chamberof such design that its cross-sectional area broadens as the powerstroke advances, allowing gases to expand radially into space where theyaccomplish no work. Most rotary engine designs also requireprecompressed fuel, with accompanying losses of energy, especiallythrough loss of heat.

The Wankel and other engines patented in recent years have suffered fromone or more of these handicaps. The engine in U.S. Pat. No. 3,882,827requires blade seals which must expand outward from their slots in arotor under heavy combustion pressures against their sides in order tomaintain sealing contact with the cylinder. The industry so far has notbeen able to make this type of seal function satisfactorily. The Wankelrotary, though it compresses its own fuel, suffers from inadequatesealing, short life seals, friction between seals and cylinder andbetween rotor and end walls, and especially from loss of energy due toradially broadening of lobed expansion chamber. Because of the shape ofthe Wankel expansion chamber, in relation to its combustion chamber andto the triangular piston, that rotary, though a simple engine, cannotmake the fullest use of the energy released during combustion.

The invention herewith provides positive sealing and sealing whichshould prove durable, and which performs with much less friction. Itinhales a charge of air and compresses it directly into the combustionchamber. It has additional features which should make it a highlycompetitive engine: it is a simple engine; it provides a great abundanceof air without extra machinery such as a turbocharger; and its expansionchamber is such that it must make efficient use of the combustion gases.The automatic availability of two and a half times as much air as aconventional piston engine of equal displacement can inhale most likelywill make this rotary adaptable for use as a diesel. The inventionengine is well suited to fuel injection with quick acceleration, fueleconomy, exceptional power per cubic inch of expansion chamber and acomparatively clean exhaust. It is obviously a high-altitude engine.Manufacturers of internal combustion engines have found that they canboost the power of an internal combustion engine by as much as 40percent by adding a turbocharger to pump extra air into the cylinders.However, turbochargers are expensive and temperamental and there is atime lag of about three seconds--a very disturbing time lag to anautomobile driver in need of a sudden surge of power for passing anothervehicle--before said turbocharger provides the power surge. In therotary design herewith, the needed air is inherently and instantlyavailable to the operator by merely depressing the acceleratorpedal--and at no extra cost, for machinery. As for the shape of theexpansion chamber, its cross-sectional area in all models actuallycontracts to some extent as the power stroke advances--somethingbelieved to be unique among internal combustion engines. In some models,the contraction is considerable. While this feature remains to betested, it seems obvious that the concentration of the dissipating gasesmust of necessity concentrate their heat and hold it longer during thepower stroke, and therefore sustain torque longer, which means gettingmore power out of a given fuel charge, burning up more of thehydrocarbons, leaving a cleaner exhaust. The invention engine isobviously a high torque engine with short stroke and an expansionchamber of large cross section. A cylinder nine inches in diameter bythree inches "long" (between end walls) with a piston seven inches indiameter, and the combustion-expansion chamber at the end of the powerstroke providing roughly 28 cubic inches volume, should be considerablymore powerful than a 56 cubic inch cylinder in a conventional four-phasecycle piston engine, since this rotary produces a power stroke with eachrevolution and is supercharged with extra air.

Designers of piston engines never are able to find as much room asdesirable for intake and exhaust valves; there is always some choking,especially at higher RPM. Both the exhaust port and the port admittingair to the combustion chamber can be proportionately larger in theinvention engine. A great wave of air can be swept in.

Another important virtue of this engine is that in a cylinder no largerthan seven inches in diameter by two and a half inches between endwalls, enough space is available for at least two spark (or glow) plugsin the combustion chamber.

The invention engine is of such design as to adapt well to modularproduction. Engine horsepower can thus be increased by merely adding oneor more cylinders (with proper timing). The modular construction shouldmake it sowewhat easier too for the manufacturer to provide for cuttingout of one or more cylinders when the engine is cruising under moderatepower. Cutting out some cylinders, letting the engine cruise on fewercylinders, should normally improve fuel economy, especially in theinvention engine, since a cylinder will be more efficient under mediumto heavy loads because of the abundance of air available.

Several automatic means of exhausting the spent gases from the expansionchamber can be used requiring no cams or gears, but all such means otherthan those claimed herein provide ports too small if they are to beclosed again automatically before the compression builds up excessivelyin compression chamber. One such automatic means with an exhaust port inat least one end wall shown and claimed herein can provide a port largeenough to be practical when the piston is comparatively large indiameter in relation to the cylinder so that the lip or flange on theedge of the piston, sealing against the end wall, can preventpressurized cooling oil in the engine from spilling out through theexhaust port when the eccentric piston is in a certain position as willbe shown. If the piston is small enough in diameter in relation to thecylinder to provide a big expansion chamber, the flange on the edge ofthe piston will strike engine shaft--thus limiting the size of theengine when this type of porting is used.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a rotary internalcombustion engine comprising a stator, a power shaft, a rotor, a piston,and first and second abutments which form the counterclockwise andclockwise ends, respectively, of the expansion-combustion chamber of theengine. The first abutment is spring biased downward toward the face ofthe engine piston with a first end pivotally secured to the stator ofthe engine, while a second free end makes tangential, sealing engagementwith the face of the engine piston during the combustion-expansionstroke of the engine. The second abutment, a rectangular metal platerigidly affixed to the engine piston and pointing radially outward fromthe center of the piston, slidably reciprocates in a slot in a pivotingbearing journaled in the engine stator as the engine piston planetates.Means for injecting fuel and air and expelling spent exhaust gases arealso provided.

A further object of the present invention is to provide a rotaryinternal combustion engine comprising a stator, a power shaft, a rotor,a piston, and first and second abutments which form the counterclockwiseand clockwise ends, respectively, of the expansion-combustion chamber ofthe engine and exhaust means for spent gases comprising a poppet valvein the perimeter of the engine combustion chamber. The first abutment isspring biased downward toward the face of the engine piston with a firstend pivotally secured to the stator of the engine, while a second freeend makes tangential, sealing engagement with the face of the enginepiston during the combustion-expansion stroke of the engine. The secondabument, a rectangular metal plate rigidly affixed to the engine pistonand pointing radially outward from the center of the piston, slidablyreciprocates in a slot in a pivoting bearing journaled in the enginestator as the engine piston planetates. Means for injecting fuel and airinto the engine are also provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end view (with end plate removed) of one version of theinvention engine with piston head at 12:00 o'clock, the point of maximumcompression.

FIG. 2 is a similar end view with piston head at 5:00 o'clock, at end ofpower stroke, showing a small jet of compressed air allowed intoexpansion chamber via a cavity in end wall, to scavenge engineimmediately after exhaust port begins to open.

FIG. 3 is a cross-sectional side view of the invention engine of FIG. 1at 12:00 o'clock showing skeletalized piston, with yieldable end seals(against end walls) and cooling oil forced through hollows of the pistonand through holes in web of rotor.

FIG. 4 is a cross-sectional side view showing lever mechanism via whichspring tension is applied to second abutment and to exhaust deflector.

FIG. 5 is a fragmented end view showing cam and cam lever outside endwall to lift second abutment from face of piston to vent engine at endof expansion stroke.

FIG. 6 is a fragmented end view showing an alternate means of applyingspring bias to hold first abutment against face of piston.

FIG. 7 is a fragmented side view of spring biasing means shown in FIG.6.

FIG. 8 is an end view of the invention engine with second abutmentflexibly tethering piston to cylinder, with pivoting leaf abutment atcounterclockwise end of combustion chamber and with poppet exhaustvalve.

FIG. 9 is a fragmented end view with cam bolted to rotor inside engine,operating a reciprocating sliding plate valve inside hollow abutment, tovent engine at end of power stroke.

FIG. 10 is a fragmented end view with piston tethered as in FIG. 9, butan alternate means of venting engine in which an annular sleeve isbolted to each side of rotor to rotate closely inside piston butclearing piston, their edges clearing the end walls and an opening inface of piston immediately counterclockwise of second abutment, viawhich opening spent gases exhaust through a box carried by sleeve, whichwith proper timing, passes under said opening; thence out by a holethrough rotor into a second box and forward on opposite side of rotor toa second opening clockwise of abutment in face of piston, the secondopening being adjacent to exhaust port in engine housing.

FIG. 11 is a side view of engine showing venting system shown in FIG.10.

FIG. 12 is a fragmented side view showing the first box with spent gasesflowing into it via opening in face of cylinder and out via hole inrotor as recited above.

FIG. 13 is a fragmented end view showing an alternate means ofexhausting spent gases from engine, in which design the second abutmentcomprises a plate-plunger pivoted in face of cylinder and slidablyreciprocating through a pivoting bearing in housing, piston tethered tohousing, preferably by a rod of small diameter of 6:00 o'clock, anexhaust port comprising a hole in at least one end wall so positionedthat oscillating second abutment uncovers the hole at end of expansionstroke, covering it again in time for combustion chamber to receivecompression charge, and a flange on edge of piston to keep pressurizedcooling oil from spilling out through the port in the end wall.

FIG. 14 is a fragment showing pivoting bearing mounted in housing withslot through which second abutment shown in FIG. 13 reciprocates.

FIG. 15 is a fragmented end view showing an alternate first abutmentwith inlet port through it and hinged cover over port.

FIG. 16 is a fragmented end view showing an optional type of firstabutment comprising a metal plate, slightly arcuate, hinged in face ofpiston and spring biased against face of cylinder, to closecounterclockwise end of combustion chamber, said spring biasing adjustedto allow said plate to spring open when pressure of air building up incompression chamber reaches a predetermined psi.

FIG. 17 is a fragmented end view of means for automatically trapping abit of compressed air from compression stroke and storing it until endof expansion stroke, then releasing it into combustion-expansionchamber, just as exhaust port opens, to scavenge engine.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An engine shaft 10 in bearings 11 is journaled in parallel end walls 12and 12a, the end walls sealing between them a cylinder bore 13 in astator 14, the bore concentric with engine shaft 10. An eccentricannular rotor 15 is keyed to shaft 10 and positioned midway between theend walls inside the engine. Annular piston 18 is fitted on eccentricrotor 15, concentrically with it, preferably with bearing 16 betweenrotor 15 and piston 18. At least one end seal 19 is provided on each endof piston 18 to maintain yieldable sliding engagement against end walls12 and 12a. Rotor 15 and piston 18 have a common head 17 at the point oftheir longest radius and piston head makes tangential sealing engagementwith cylinder 13 throughout a cycle, which is one revolution of theengine shaft. A first abutment 22 positioned preferably near 10:00o'clock forms a sealing bridge between cylinder 13 and piston 18, fromend plate to end plate, and comprises the counterclockwise end of acombustion-expansion chamber 21. A combustion subchamber 21a comprises ashallow arcuate cavity in stator 14 centered about 12:00 o'clock, thecavity being adjacent to but out of the path of piston 18, andcommunicating with cylinder bore 13. At least one spark plug (or glowplug) 31 is mounted in combustion chamber 21. A second abutment 23positioned preferably near 2:00 o'clock seals the space between cylinder13 and piston 18, from end wall to end wall, and forms the clockwise endof combustion-expansion chamber 21. A port 35 in stator 14 at about 3:00o'clock is fitted with a one-way inlet valve 36 to admit air to engine.Piston head 17 together with second abutment 23 forms an air suctionchamber to clockwise of second abutment, and an air compression chamberto clockwise of said piston head. Various means are available forporting combustion-expansion chamber 21, as various types andcombinations of fist and second abutments may be used, and some of themeans of porting for air intake and for exhausting the spent gases areadaptable only with certain types of abutments.

A preferred type of first abutment 22 (FIGS. 1 and 2) comprises arectangular plate of rigid material, such as aluminum, one end of itwith rounded head, which head is journaled in a bore in statorpreferably near 10:00 o'clock, the bore parallel to engine shaft 10, theother end of the abutment projecting clockwise and free to swingvertically in chamber 21 between piston 18 and cylinder 13. The cylinderis machined away along the edges of bore 13 to make room for abutment 22to pivot. Stator 14 is recessed just above abutment 22 to make room forabutment 22 while piston head 17 passes. The lower face of abutment 22is arcuate on a radius equal to the radius of cylinder 13 to allowabutment 22 to become an extension of the compression chamber as thecompression stroke ends. Abutment 22 can be opened automatically by airpressure or it can be lifted by cam 53a keyed to shaft 10 outside theengine, the lifting function performed via cam-following lever 58a whichis keyed to a hub 24 on end of abutment pivot head, which hub isjournaled in end plate and extends outside to receive lever 58. Pivotingabutment 22 is biased downward toward piston 18 by spring 27 mounted onpost 28 on outside of end plate, the spring impinging on knob 26 on freeend of arm 25, which arm is keyed to hub 24. Spring tension can also beapplied from the side of cylinder bore 13 against stud 22m screwed intopivot head 22b through an opening 22h in stator 14.

A second optional type of first abutment comprises a rectangular hollowabutment 71 (FIG. 15) with rounded head 78 on one end, journaled inpiston 18 in a bore parallel to engine shaft 10, the piston recessed oneach side of the abutment along edges of the bore to allow the piston toplanetate. The abutment is mounted to reciprocate slidably inside a slot75 in stator 14 pointing radially outward from the center of cylinder13, abutment 71 provided with a window 83 through which air can becompressed from compression chamber 20 directly intocombustion-expansion chamber 21. Plate 110 on hinge 111 is forced openby compressed air in chamber 20 against adjustable tension of spring 113and is closed again across window 83 by combustion pressures in chamber21. A friction plate 73 on the side of abutment where wear is heaviestis readily removable for replacement by removing cover plate 88. Afret-like yieldable seal 30 is mounted in a slot in the housing to sweepthe face of the reciprocating abutment on its high pressure side.

A third type of optional first abutment closing the counterclockwise endof combustion-expansion chamber 21 (FIG. 16) comprises a rectangularplate of metal 22', preferably lightweight, with rounded head 22r on itsinner end, head 22r forming a pivot and journaled in a bore in the faceof piston 18 preferably near 10:00 o'clock. Spring bias is applied to anarrow projection 22s on the inside of pivot head 22r, on at least oneside between rotor 15 and the end wall, through a narrow slot in piston18. Spring 22t is anchored on the underside of piston 18 between rotor15 and the end wall. Plate 22' is somewhat arcuate and flexibly slidesagainst cylinder bore 13 to close counterclockwise end ofcombustion-expansion chamber 21, yet is yieldable to air pressure incompression chamber 20.

A preferred type of second abutment closing the clockwise end ofcombustion-expansion chamber 21 comprises a rectangular metal plate 23(FIGS. 1, 2, etc.) with rounded pivot head 24 journaled in the face ofcylinder 13 at about 2:00 o'clock, the other end of plate 23 free toswing in an area inside the space between piston 18 and combustionchamber 21a. Plate 23 is slightly arcuate to conform roughly withcylinder bore 13, its free swinging end held tangentially against theface of piston 18 by spring 27 mounted on post 28 outside end wall 12.Spring 27 bears against knob 26a (FIG. 5) on lever 58 which is keyed tohub 24 on end of pivot head. A cam 53 on engine shaft 10 outside endwall 12 is designed to lift abutment 23 off the face of piston 18 at endof the expansion stroke to let spent gases spill out between abutment 23and the face of piston 18 into exhaust port 32, cam 53 allowing abutment23 to close again in time for combustion chamber 21 to receive nextcharge of compressed air.

An optional type of second abutment (FIGS. 8 and 10) comprises a metalplate 67 rigidly fixed to piston 18 and projecting radially outward fromcenter of piston, plate 67 coextensive with end walls 12 and 12a andpreferably fitted with a yieldable rib seal 66 along each edgecontacting the end walls, the rib seals connected across the face of theabutment by rib seal 66a. The abutment is mounted slidably through aslotted pivoting bearing 64 in stator 14, optionally with needlebearings 74 along the high friction side of the sliding abutment.

Another optional type of abutment, closing counterclockwise end ofchamber 21, comprises a hollow abutment 67a (67b) (FIG. 9) rigidly fixedto piston 18 and slidably reciprocating through pivoting bearing 64b instator 14 centered preferably near 2:00 o'clock. Metal plate 77cslidably mounts in hollow of abutment 67a and 67b while an arm of plate77c projects through a narrow slot in the face of piston 18 on each sideof rotor 15, and bears against a cam 15a bolted to rotor 15 near itsperimeter, the plate spring-biased inward, and the cam designed andpositioned to permit the plate to slide inward at the end of theexpansion stroke to bring a window 83b through plate 77c into matingposition with window 83a through the abutment, letting spent gases spillout of expansion chamber 21 into exhaust port 32. Cam 15a is designed toreturn plate 77c to its original position, closing exhaust port 32 intime for combustion-expansion chamber 21 to receive the next charge ofcompressed air. Deflector 33 is spring biased against the face of piston18 to deflect spent gases out via port 32.

Still another optional type of second abutment, which can be used in anengine wherein the piston is as large as about 21/24th the diameter ofthe cylinder, and the combustion-expansion chamber thereforcomparatively small, comprises a rectangular plate 67 (FIG. 13) withrounded head 69 on its inner end, the head pivotally journaled in abearing in the face of piston 18, and piston 18 machined away alongedges of bore to allow the abutment to flex clockwise andcounterclockwise as piston 18 planetates. The abutment is mountedslidably through a slot in pivoting bearing 64a in stator 14. Piston 18is tethered to cylinder 13, preferably by a rod 59 of small diameter ina pivoting bearing 60 in stator 14 at about 6:00 o'clock. Port 68 in atleast one end wall is so positioned that the abutment must pass over itand uncover it at the end of the expansion stroke to let spent gasesspill out via exhaust port. A flange 18b along edge of piston 18 andjust clearing engine shaft 10 in all positions of the piston, fittedwith yieldable seal 19a along its inner edge, prevents pressurizedcooling oil from spilling out of the engine.

An optional means of venting the engine at the end of the expansionstroke, other than means already described herein, comprises a poppetvalve 9 (FIG. 8) with valve stem 9a through stator 14 in the perimeterof combustion chamber 21a with exhaust port 9b. Poppet valve 9 isoperated by a cam not shown.

Another optional exhaust means without need of cams or gears, wherepiston 18 is tethered by second abutment 67 rigidly fixed to piston 18(see FIGS. 10, 11 and 12), comprises a sleeve 202 on each side of rotor15 and attached to the rotor, sleeves 202 virtually coextensive with theend walls 12 and 12a and rotating closely but not engaging the undersideof piston 18 with suitable seals acting yieldably against the undersideof piston 18. Box 202a on one side of rotor 15 and open at the topreceives spent gases at the end of the power stroke when the box passesunder and mates with an opening 70a through rotor 15 adjacent to andconnecting with the box and connecting into a second box 201' on theopposite side of rotor 15. Second box 201' is elongated in a clockwisedirection to pass under the inner end of abutment 67 and deliver spentgases out via port 207' in the face of that side of piston 18, gasesthence passing out of engine via exhaust port 32. Yieldable seals in theperiphery of sleeves 202 engaging the underside of piston keep bothopenings in piston 18 closed except while engine is being scavenged.

A means of insuring adequate scavenging of engine even when a minimum ofair is allowed to enter compression chamber 20 comprises a small port152 (FIG. 17) in an end wall near the perimeter of compression chamber20 and a few degrees counterclockwise of the first abutment. A pipe 151fitted over port 152 and fitted with a check valve indicated by arrow153 leads to a small container 150 to store a small amount of compressedair during the compression stroke. A larger pipe 154 leads from storagecontainer 150 to a second port 155 in an end wall. Port 155 is sopositioned that it will remain covered by a flange 19a on edge of piston18 throughout the expansion stroke but will be uncovered just after theexhaust port opens allowing the stored compressed air to spill into theexpansion chamber to force out spent gases. The means described hereinis entirely automatic.

While certain combinations of first and second abutments are shown inthe accompanying drawings, certain other combinations can obviously beused. For example, a poppet valve for exhausting of spent gases can beused with the two pivoting leaf abutments shown in FIG. 1, in whichcombination the first leaf abutment can be opened by air pressure whenpressure reaches a predetermined psi, and the second abutment remains atall times in sealing contact with the face of the piston, and camsoutside the end walls are eliminated. Also, the type of second abutment67a (67b) shown in FIG. 9 can be adapted for use as a first abutment bychanging the shape and timing of the cam 15a bolted to rotor 15.

METHOD OF OPERATION

This rotary engine has the four phases of intake, compression, expansionand exhaust with each revolution of the engine shaft. FIG. 1 shows apreferred embodiment with rotor head 17 at 12:00 o'clock, the point ofmaximum compression of a charge of air. (Since the piston head is commonwith the rotor head, it too shall be identified herein by the number17.) Fuel now may be injected into combustion chamber 21a via port 59 inend plate 12 (FIG. 3) and ignited by one or more spark (or glow) plugs31, or fuel optionally has already been injected at port 49 in end plateinto inflowing compressed air, to be ignited by one or more spark (orglow) plugs 31. Compression charge is confined between abutments 22 and23. After ignition, expanding gases bear against piston 18, which exertsdownward pressure on rotor head 17, causing rotor 15 to rotate, andbeing keyed to engine shaft 10, the rotor converts the downward pressureinto rotary motion. As rotor 15 advances clockwise, it sucks into theengine via intake port 35 and one-way inlet valve 36 air from theoutside and at the same time compresses the air drawn in during thepreceding revolution against abutment 22, which is held against piston18 by preset spring tension and, throughout the power stroke, also bythe pressure of expanding gases inside the combustion chamber. Firstabutment 22 is opened by cam 53a outside end wall 12 or, optionally, bycompressed air when it reaches a predetermined psi. When the piston headreaches the end of the power stroke at a point preferably near 5:00o'clock, cam 53 outside end plate 12 lifts swinging abutment 23 offpiston 18 via lever 58 keyed to pivot hub 24, allowing spent gases toflow out of the combustion chamber into the space between the piston andthe cylinder. These spent gases are deflected outside engine throughport 32 by a thin rectangular strip of metal 33 which seals between theend walls, and is anchored by pivot to stator 14, and is spring biasedagainst piston 18 by a spring outside the end wall via a lever keyed tohub 34 on end of pivot, which hub is journaled in the end wall. A jet ofcompressed air is admitted into the combustion chamber via a narrowcavity 91 hollowed out on the inner face of at least one end plate andso positioned that the free end of swinging abutment 22 lies across thecavity at the end of the power stroke immediately after exhaust port 32opens, the jet of air being an aid to scavenging engine. Exhaust port 32is closed by spring tension or optionally by cam action (FIG. 5), cam 53so shaped as to quickly return abutment 23 to sealing position againstpiston 18.

While the chief functions of this engine are the same in allcombinations of first and second abutments and various exhaust means,the mechanical differences shown in FIG. 8 are considerable. The intakeand compression action is the same as previously recited, but the secondabutment comprises a metal plate 67 coextensive with the end walls,rigidly tethered to piston 18, and slidably reciprocating through apivoting bearing 64 in stator 14, the mechanism allowing piston 18 toplanetate as off-center rotor 15 rotates. Poppet valve 9 functions asexhaust port.

In the combination shown in FIGS. 10, 11, and 12, the intake andcompression action is the same as recited above, but any of the firstabutments can be used. The second abutment is rigidly fixed to thepiston and reciprocates in a pivoting bearing 64 in stator 14 and theexhaust is by means fully automatic: the sleeve 202 bolted to each sideof rotor 15 and rotating close to the underside of the planetatingpiston 18 allows the spent gases to spill out of expansion chamber 21via a port 70a' in the face of piston 18 into a box 202a and through ahole 210 in rotor 15 adjacent to and connecting with box 202a, andthence into a second box 201' on an opposite side of rotor 15, thesecond box being elongated to extend forward and allow the spent gasesto spill out to clockwise of second abutment 67 via port 207' in theface of piston 18 and out of the engine via exhaust port 32. Perimeterseals 19a and cross seals 19b make yieldable sealing contact withunderside of piston 18. Additional cross seals may of course be providedas needed.

Since this engine fires every revolution, it is necessary to close theexhaust port quickly after the end of the expansion stroke before aircompression reaches more than a few psi in the compression chamber. Itmay be noted that all exhaust means shown herein are designed to providethe required prompt closing so that a minimum of air will be forcedthrough the expansion chamber, even when under maximum air charge.

It may be noted that when the engine is under very light load, with aminimum of air admitted to compression chamber 20, only a very smallamount of air will be available to scavenge the engine. Not much airwill be required, of course, when the combustion charge is very small.But auxiliary scavenging air can be provided by means entirely automaticby the device shown in FIG. 17. A small charge of compressed air isforced into storage tank 150 via the small pipe or tube 151 (which isfitted with a one-way valve at 153), through port 152 located near theclockwise end of compression chamber 20. The stored air is held instorage tank 150 by flange 19a on the edge of piston 18, which flangecovers the discharge port 155 throughout combustion and until the end ofthe power stroke. Just after exhaust port (not shown in FIG. 17) opens,the rim of piston 18 passes downward uncovering port 155 and letting thecompressed air spill into the expansion chamber.

In a variation of this means of cleansing the engine at the end of thepower stroke, there is an adjacent pair of windows like 70a' (FIGS. 10,11 and 12) in the face of piston 18 counterclockwise of abutment 67 andon opposite sides of rotor 15. An adjacent pair of similar windows inpiston 18 like 207' are on the clockwise side of abutment 67 and onopposite sides of rotor 15. An adjacent pair of windows in rotatingsleeves 202 are on opposite sides of rotor 15, each sleeve windowsubtending a box the same length and width as the window, its lengthbeing such that it exactly spans both piston windows in its path. Thus,when the sleeve windows begin to engage the piston windows on thecounterclockwise side of abutment 67, spent gases in the combustionchamber begin to escape into the boxes and as soon as the boxes begin toengage the second pair of piston windows, they form two exhaust channelsvia which the spent gases pour out of the expansion chamber into theengine space clockwise of abutment, adjacent to the exhaust port.Yieldable seals are provided between the surfaces of the sleeves and thepiston to prevent combustion gases from escaping except at the end ofthe expansion stroke and to again seal clockwise end ofcombustion-expansion chamber as soon as the sleeve boxes pass the pairof piston windows on the counterclockwise side of abutment 67.

Test engineers have been unable to seal rotary engines well enough tomeet commercial requirements. Though Wankel is on the market in limitedvolume, and its end seals have proven satisfactory, its apex seals losecompression and they wear rapidly. A great many rotary engines shown inpatent drawings depend only on contact between rotor and cylinder forsealing. Such contact sealing has been adequate for rotary aircompressors up to about 300 psi; but it has not been satisfactory incontaining combustion pressures which may range up to 2,000 psi.Numerous rotary designs depend on sliding vane or blade seals, but thistype of sealing has proved unsatisfactory because the pressure ofcombustion gases against the sides of the vanes binds them in theirslots.

It is believed that the only sealable type of rotary engine designedto-date is the type shown herein in which a first and a second abutment,together with the piston and cylinder, form a combustion chamber andalso remain in contact with the cylinder and the piston throughout theexpansion stroke. The design has additional virtues. It is simple,requiring a minimum of machining and materials. Most rotaries allow theexpanding gases to flow around the rotor, pushing the rotor head. These,for the most part, provide also a widening expansion chamber, thevolumetric clearance causing a loss of efficiency. Also, the combustiongases cool excessively as they flow against the cooling jacket. Theinvention engine confines the combustion gases to an expansion chamberwhich seems to be unique in internal combustion engines: one in whichthe cross-sectional area, instead of remaining the same as in a pistonengine, or widening as in most rotaries, the expanding gases areconfined to an area which actually narrows as the stroke advances, thusretaining the heat of combustion for a longer portion of the powerstroke.

The design of the present invention engine also provides a great volumeof air for the combustion chamber, since the gases of combustion areconfined to the upper part of the cylinder, leaving more thanthree-fourths of the cylinder to function as an air compressor. Thisengine can inhale two and one-half to three times as much air as apiston engine of equal displacement (without a supercharger). The goodsealing and the large quantity of air enables this engine to function asa diesel. The abundance of air also insures quick and thoroughscavenging, even though this engine fires a charge every revolution.Having no cam shafts, cams, mountings, and a rotor which does not scrapethe end walls, the invention engine obviously will be exceptionallyquiet and smooth in operation, even though a diesel.

While the invention has been described in connection with the preferredembodiment, it is not intended to limit the invention to the particularforms set forth, but, on the contrary, it is intended to cover suchalternatives, modifications, and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claims.

I claim:
 1. A rotary internal combustion engine having a four-phasecycle of intake, compression, expansion and exhaust in each revolutionof the engine shaft, the engine comprising:a stator with a cylinder boreenclosed between end walls; a power shaft in bearings journaled in theend walls and concentric with the cylinder bore; an eccentric annularrotor keyed to the power shaft and positioned approximately midwaybetween the end walls; an annular piston coextensive with the end wallsand fitted on the eccentric rotor and concentric with it, the piston androtor having a common eccentric head, the piston head making tangentialsealing engagement with the cylinder substantially throughout the cycle;a first abutment having a first end pivotally secured to the stator near10:00 o'clock and a second end free to project clockwise into thecylinder space far enough to make tangential, sealing engagement withthe face of the piston in all positions of the piston, the abutmentmaking sliding sealing engagement with both end walls and, during thecombustion-expansion stroke, making sealing engagement with the face ofthe piston, thus forming the counterclockwise end of acombustion-expansion chamber for confining a charge of fuel throughoutan expansion stroke and exerting pressure against the piston to causethe piston to force the eccentric rotor to rotate, the cylinder machinedaway along the edges of the pivot bore in the stator to permit theabutment to pivot inside the cylinder as the piston planetates, theabutment spring biased downward toward the face of the piston by aspring mechanism outside the engine, allowing a predetermined pressurein the compression chamber to force the abutment open and permit acharge of air to be compressed into the combustion chamber and to aid inholding the free end of the abutment in sealing engagement with the faceof the piston at the end of the compression stroke; a second abutmentclosing the clockwise end of the combustion-expansion chamber comprisinga rectangular metal plate rigidly affixed to the piston and coextensivewith the end walls and pointing radially outward from the center of thepiston, the second abutment inserted through a slot in a pivotingbearing journaled in the stator near 2:00 o'clock to slidablyreciprocate in the slot, the stator machined away along the edges of thebore for the pivoting bearing to enable the second abutment to swingclockwise and counter-clockwise as the piston planetates; a combustionchamber comprising a shallow arcuate cavity in the stator centered near12:00 o'clock and opening into and combining with the expansion chamber;a suction chamber and a compression chamber, the suction chamber beingthe space behind the traveling piston head and the compression chamberbeing the space forward of the traveling piston head; an air inlet portin the stator positioned in the vicinity of 3:00 o'clock, the portfitted with a one-way valve to admit air into the suction chamber asmovement of the piston head generates a suction; means for injecting acharge of fuel into the combustion chamber and means for firing the fuelcharge in timed relation to the position of the piston head; exhaustmeans for expelling spent gases from the combustion-expansion chamber atthe end of the power stroke, the means comprising a poppet valve in theperimeter of the combustion chamber.